1. Field of the Invention
The present invention relates to fuel cells and a fuel cell system. More particularly, the invention relates to fuel cells each including an electrolyte layer in the form of a plate, an oxygen electrode applied to one surface of the electrolyte layer, a fuel electrode applied to the other surface of the electrolyte layer, and a gas passage defining device formed of a conductive material and opposed to the oxygen electrode or fuel electrode for defining oxygen-containing gas passages or fuel gas passages; and to a fuel cell system using such cells.
2. Description of the Related Art
FIG. 11 shows a cell C of this type known in the art.
This cell C includes a separator 31 formed of a conductive material and having a plate portion 31a and a pair of strip-shaped projections 31b extending along opposite ends of the plate portion 31a. The separator 31 is attached to an oxygen electrode 2 (or fuel electrode 3), with the strip-shaped projections 31b contacting opposite edges thereof, respectively. A plurality of conductive columnar members 32 are arranged between the separator 31 and oxygen electrode 2 (or fuel electrode 3). Thus, the separator 31 and oxygen electrode 2 (or fuel electrode 3) are connected in conductive state to each other, with a plurality of groove-like oxygen-containing gas passages "s" (or fuel gas passages "f") formed between the pair of strip-shaped projections 31b.
That is, a gas passage defining device R is formed of the separator 31 and the plurality of columnar members 32 formed separately from the separator 31.
A fuel cell system is composed of a plurality of such cells C stacked one over another in a spaced relationship to define fuel gas passages "f" (or oxygen-containing gas passages "s".
However, the conventional fuel cells involve a high manufacturing cost since the separator and columnar members must be manufactured separately. Furthermore, the cell manufacturing process is complicated by the necessity to arrange the plurality of columnar members between the separator and oxygen electrode (or fuel electrode) in addition to a step of attaching the separator to the oxygen electrode (or fuel electrode).
Moreover, since the oxygen electrode and fuel electrode are formed porous to be permeable to gases, it is necessary to seal positions of contact between the strip-shaped projections and oxygen electrode (or fuel electrode) to prevent gas leakage. This further complicates the cell manufacturing process.
The fuel cell system constructed of such fuel cells having the above drawbacks requires a high manufacturing cost as well as a complicated manufacturing process.